Long-term follow-up of allogeneic HSCT for CML reveals significant improvement in the outcome over the last decade.

Allogeneic hematopoetic stem cell transplantation (HSCT) is still the only curative therapeutic option for chronic myelogenous leukemia (CML). To examine the development of allogeneic HSCT at our center over the past two decades (decade 1: 1984-1994; decade 2: 1995-2005), all CML patients transplanted in first chronic phase (n = 234) were analyzed with respect to patient characteristics, overall survival, transplant-related mortality (TRM), and relapse incidence. The median follow up time was 54 months (range 1-218). The incidence of acute graft vs host disease (GvHD) degrees II-IV and extensive chronic GvHD were not different between the two decades (p = 0.894 and p = 0.422, respectively). There was also no difference in the relapse incidence (23 vs 26%, p = 0.869). One-year TRM and overall survival were improved in the later decade (33 vs 18%, p = 0.011 and 62 vs 73% at 5 years, p = 0.063, respectively). The major reason for improved outcome in decade 2 was the improved management of acute GvHD and infections in the early phase after transplantation (p = 0.026). In conclusion, the past decade has seen significant improvement in the performance of allogeneic HSCT for CML.

Graft-versus-Leukemia Effect Following Hematopoietic Stem Cell Transplantation for Leukemia.

The success of hematopoietic stem cell transplantation (HSCT) lies with the ability of the engrafting immune system to remove residual leukemia cells via a graft-versus-leukemia effect (GvL), caused either spontaneously post-HSCT or via donor lymphocyte infusion. GvL effects can also be initiated by allogenic mismatched natural killer cells, antigen-specific T cells, and activated dendritic cells of leukemic origin. The history and further application of this GvL effect and the main mechanisms will be discussed and reviewed in this chapter.